Heat sealable isotactic polypropylene and 1,3 pentadiene polymer

ABSTRACT

A resinous blend composition, and thermoplastic film structures fabricated therefrom having improved physical properties, comprising a polyolefin (e.g., polypropylene) containing a minor amount based on the weight of the polyolefin and sufficient to improve the heat sealing characteristics of films fabricated from such blends, of a normally solid, resinous, random multipolymer of a mixture comprising pentadiene, 1,3 and at least one other hydrocarbon compound containing ethylenic unsaturation copolymerizable therewith. Examples of such ethylenically unsaturated hydrocarbons include cyclopentadiene, isoprene, 2methylbutene-2, tertiary butylstyrene, Beta -pinene, dipentene, Beta -phellandrene, Alpha -methylstyrene, and mixtures thereof.

United States Patent 1191 Nahmias et al.

[ 51 Feb. 11, 1975 1 HEAT SEALABLE ISOTACTIC POLYPROPYLENE AND 1,3PENTADIENE POLYMER [75] Inventors: Michael A. Nahmias, Canandaigua,

N.Y.; Edward M. Bullard, South Orange, NJ.

[73] Assignee: Mobil Oil Corporation, New York,

[22] Filed: Apr. 16, 1973 [21] Appl, No.: 351,211

[52] US. Cl 260/889, 260/80.7 [51] Int. Cl. C08d 3/04, C08f 29/12 [58]Field of Search 260/889, 80.7

[56] References Cited UNITED STATES PATENTS 3,278,646 10/1966 Lambert,.lr.. 260/897 3,478,005 11/1969 Wheeler 260/80.7 3,509,239 4/1970Tindall 260/889 Primary Examiner-Murray Tillman Assistant ExaminerJ.Ziegler Attorney, Agent, or Firm-Andrew L. Gaboriault; Mitchell G.Condos; James D. Tierney [57] ABSTRACT 16 Claims, N0 Drawings HEATSEALABLE ISOTACTIC POLYPROPYLENE AND 1,3 PENTADIENE POLYMER BACKGROUNDOF THE INVENTION 1.Field of the'lnvention The present invention relatesto resinous thermoplastic blend compositions suitable for employment inthe fabrication of thermoplastic films and, in particular, orientedthermoplastic films such as oriented polypropylene. Certain uncoated,oriented films such as polypropylene have relatively high heat sealingtemperatures and narrow heat sealing ranges in contrast to otheravailable thermoplastic films such as polyethylene, for example.Additionally, oriented films such as oriented polypropylene exhibit atendency to disorient, shrink, and tear when attempts are made to heatseal them at their prerequisitely high heat sealing temperature.

In accordance with the present invention, a minor amount (e.g., fromabout 5 percent to about 40 percent by weight) of a normally solid resininterpolymer of pentadiene with at least one other hydrocarbon havingethylenic unsaturation copolymerized therewith, is blended withpolypropylene resin prior to extrusion of the polypropylene into a filmstructure. Specific embodiments of such normally solid resins include amultipolymer of a mixture of pentadiene, isoprene, cyclopentadiene andat least one of the following: 2- methylbutene-Z, t-butyl-styrene,B-pinene, B-phellandrene, dipentene, a-methylstyrene and mixturesthereof; and still more specifically, such multipolymers derived from amixture comprising pentadiene and 2- methylbutene-Zas its majorcomponents (and preferably in about equal parts by weight); mixturesthereof with t-butylstyrene, or with beta-pinene, or with a mixture ofalpha methyl styrene, dipentene and betaphellandrene. Orientedpolypropylene film structures prepared from such resinous blend mixtureshave been found to exhibit substantially lower minimum heat sealtemperatures, thereby broadening its heat seal range. The interpolymercontaining film has improved optical properties and a significantlyimproved, or higher, tensile modulus or stiffness thereby improving thefilms processability on automatic packaging equipment.

The heat sealing characteristics of the novel film compositions of thepresent invention may be further improved by subjecting such films toelectronic treatment such as corona discharge treatment utilizingtechniques which are well known in the art.

2. Description of the Prior Art U.S. Pat. No. 3,278,646 describes theemployment of terpene polymers, such as B-pinene for example, inadditive amounts to improve the heat seal characteristics of orientedpolypropylene film. However, such blends have, in instances, been foundto have poor surface properties, increased blocking, narrow sealingranges and poor dimensional stability. Other attempts to remedy the heatsealing difficulties of such oriented films include providing the filmwith a coating of material that is more heat sensitive and hencescalable at a lower temperature than the film itself. However, suchcoating techniques are both time consuming and costly, involving theformulation of special coating materials, special treatment of the filmsurface to insure coating adhesion as well as necessitating theemployment of film coating equipment. Additionally, in many instancessuch coatings have been found to have an adverse effect on film physicalproperties such as increasing the blocking tendency of the coated films,reducing the film optical properties, and causing higher coefficients offriction.

SUMMARY OF THE INVENTION In accordance with the present invention,resinous compositions are provided which may be employed in thefabrication of oriented polypropylene film which exhibits lower minimumheat seal temperatures, broadened heat seal temperature ranges andincreased tensile modulus when compared to oriented polypropylene filmswhich do not contain the modifying additive embodied for use herein. Thenovel resinous blend compositions of the present invention comprisepolypropylene resin, as well as blends thereof with other thermoplasticresinous materials such as polybutene and copolymers thereof such asethylene butene-l copolymer, in admixture with a minor amount sufficientto improve the heat sealing characteristics of the film fabricated fromsuch blends, as for example on the order of from about 5 percent toabout 40 percent by weight, and preferably from about 10 percent toabout 30 percent by weight of a random, normally solid resininterpolymer of pentadiene with at least one other hydrocarbon havingethylenic unsaturation as hereinafter defined. The normally solid resinmay be prepared by copolymerization of pentadiene 1-3 with a hydrocarboncompound containing ethylenic unsaturation, such as, for example, methylbutenes, tertiary butylstyrene, beta-pinene, B-phellandrene, dipentene,a-methylstyrene and mixtures thereof. Normally solid resinousinterpolymers, as embodied for use herein, can be synthesized byemploying conventional Friedel-Crafts (e.g., aluminum chloride)catalyzed polymerization reactions of mixtures comprising pentadiene andsaid other copolymerizable hydrocarbons as more fully described herein.Particularly preferred are such interpolymers that have a melting pointin the range of about to about C (ring and ball).

DESCRIPTION OF SPECIFIC EMBODIMENTS The interpolymer materials which maybe used in accordance with the present invention to improve orientedfilm properties are random, normally solid, resinous multipolymers whichinclude (A) interpolymers of pentadiene with another hydrocarbon havingethylenic unsaturation copolymerizable therewith (e.g. diolefins,including cyclopentadiene and isoprene), and (B) copolymers of (A) inmixture with one or more of the following: methylbutene; tertiarybutylstyrene; betapinene; admixtures of B-phellandrene, dipentene anda-methylstyrene. A particularly suitable mixture for preparation of suchinterpolymers, is a mixture of pentadiene 1-3 and another diolefin ordiolefins and, more specifically, a mixture containing as its maincomponents pentadiene 1-3 and 2-methylbutene-2. One source of suchmixture is a byproduct in the steam cracking of hydrocarbons for theproduction of ethylene or propylene and a specific example of which isthe following comprising a mixture of C hydrocarbons as the majorcomponent:

3,3 dimethyl butene-l 1.1 l trans pentene-Z 5.85 cis pentene-Z 3.09Z-methylbutene-Z 35.80

-Continued 4-methylpentene-l and The above olefin stream, containing ahigh percentage of pentadiene 1,3, is hereinafter referred to as thepiperylene concentrate stream employed as the polymerizable mixture forpreparing the interpolymers in illustration of specific embodiments ofthe invention.

Such polymerizable mixtures may per se be polymerized, for use asembodied herein, or in admixture with another ethylenically unsaturatedhydrocarbon such as tertiary butylstyrene, B-pinene, dipentene,B-phellandrene a-methylstyrene and mixtures thereof to yield themultipolymer resins employed in the present inventron.

In accord with the present invention, it is preferred that themultipolymer resins employed be produced from resinous mixtures whichhave pentadiene concentrations present in amounts ranging from about toabout 75% based on the weight of the polymerizable mixture. Morespecifically, pentadiene concentrations in the range of from about toabout 65% by weight may be advantageously employed to produce themultipolymer resins. For example, when multipolymers are produced frompiperylene concentrate-tertiary butylstyrene mixtures, pentadiene 1,3concentrations present in the polymerizable mixture may preferably rangefrom about 15% to about 40% based on the total weight of polymerizablemixture. More specific embodiments include a polymerizable mixturecomprising in weight ratio about 30 to about 80% of an approximatelyequal part by weight of a mixture of pentadiene 1,3 and methylbutene andto 70% of t-butyl styrene. 1n the case of polymerizable mixturescomprising piperylene concentrate, dipentene, beta-phellandrene andalphamethylstyrene, pentadiene 1,3 concentrations in the polymerizablemixture may preferably range from about 15% to about 30% by weight. Morespecific embodiments include a polymerizable mixture comprising byweight from about 15 to about 30% pentadiene 1,3, 20-40%alphamethylstyrene, 530% dipentene and 2 to 15% beta-phellandrene. Itshould be understood however that the pentadiene 1,3 concentrations inthe foregoing polymerizable mixtures are only preferred ranges andconcentrations of pentadiene 1,3 outside such ranges may also besuitably employed.

U.S. Pat. Nos. 3,457,632 and 3,622,551, the disclosures of which areincorporated herein by way of reference, disclose olefinic mixtures ofthe type which may be employed in preparing the interpolymers useful inpractice of the present invention.

rachloride and the like with the aluminum chloride being a preferredembodiment. During the progress of the polymerization reaction, thereaction temperature is maintained within a range which desirably issuitable for relatively rapid polymerization without reaction surge,such as a temperature within the approximate range of 0 C. to about C.Friedel-Crafts catalyzed reaction techniques suitable for use inpreparing the normally solid resinous additives employed in the presentinvention are described in aforenotes in U.S. Pat. Nos. 3,467,632 and3,622,551.

In accord with the present invention, it is preferred that the normallysolid resinous, interpolymer materials exhibit a melting point range(Ring and Ball) of from about 70 C up to about C.

The polypropylene resins which are particularly suitable for employmentin the present invention are essentially isotactic, crystallinepolypropylenes which exhibit the following range of properties:

Melt Flow lndex 0.5 l2 Crystalline Melting Point (F.) 305 340 lnherentViscosity 1.4 4.0

Molecular Weight (Weight Average) Density (grams/cc.)

EXAM PLE l A random multipolymer was prepared by anhydrous aluminumchloride catalyzed interpolymerization in toluene ofa mixture comprisingby weight 55.3% of the piperylene concentrate hereinbefore described;9.7% of a mixture comprising dipentene and ,B-phellandrene present in aweight ratio of about 2:1, respectively; and 35.0% of a-methylstyrene.

(in nitrogen) The resinous interpolymer, when heated under nitrogen at arate of 10 C. per minute, had an initial decomposition temperature of205 C;'a 0.0% weight loss at 200 C. a 12.8% weight loss of 300 C.; and a90.0% weight loss at 400 C.

Such a resinous multipolymer was admixed with molten polypropylene resinby mixing at a temperature of about 350 F. in a Brabender Plasticorderfor about 20 minutes. The polypropylene resin employed was a highisotactic, crystalline polypropylene having the following properties:

Melt lndex 4-5 Crystalline Melting Point (F) 330340 Inherent Viscosity1.4-1 .6 Molecular Weight 100,000-120,000 Density (grams/cc.) 0910-0890Following mixing, the blend was molded into plaques approximately 25mils thick. The individual plaques were biaxially oriented attemperatures within the range of from about 280 F. up to 310 F., bystretching the plaques about 620 percent in one direction andsubsequently stretching the monoaxially oriented plaque, in a directionperpendicular to the first stretch direction, about 400 percent. Thefinal gauge of the additive containing biaxially oriented film sampleswas about 0.75 mil. The film samples were subsequently subjected to acorona discharge treatment to obtain a treatment level corresponding toat least 36 dynes/cm. wetting tension on one side of the film surface.

In the following Table I, various physical properties of the biaxiallyoriented films, produced as described in Example I are given andcompared to the biaxially oriented polypropylene film devoid of theinterpolymer as well as to biaxially oriented film containing a priorart additive, namely, beta-pinene. The percentage levels are expressedas percent by weight based upon the total weight of the additivecontaining sample.

TABLE I Additive None Example 1 Multipolymer B-Pinene Additive by wt: 1020 30 30 Haze 2.0 1.8 1.7 2.0 0.3 Gloss 36 86.9 88.1 83.8 92 Modulus MD(MPSl) 488 429 372 373 352 TD 430 399 406 406 535 Elongation MD 50 30 507O 95 TD 60 40 50 50 70 Ultimate MD (MPSl) 20.1 17.6 14.9 12.7 15.0 TD23.6 18.9 18.5 13.6 22.0 Yield MD (MPSI) 8.06 5.5 6.2 3.2

TD 8.53 5.3 6.9 6.4 10.3 Heat Seal Strength (gr/inch) Seal Bar Temp Fpsi 200 0 O 60 4O 20 2 sec. 210 0 75 60 25 220 0 5,0 120 120 40 230 0 3O50 75 45 240 0 165 25 90 50 250 O 110 80 45 40 260 0 50 170 90 60 270 045 55 110 80 280 5 85 90 90 155 290 50 195 145 180 As is apparent fromthe data in Table I, the interpolymer-containing films of the presentinvention exhibited considerably increased heat seal strength and asignificantly broadened heat seal temperature range in comparison to thepolypropylene film sample devoid of the interpolymer. Additionally, asshown, the interpolymer-containing film showed improved tensile modulusas well as superior optical properties. As also shown in Table I, thefilm structures of the present invention, when contrasted to filmscontaining the prior art fi-pinene additive, exhibit superior heat sealcharac- I teristics as well as improved tensile modulus.

The heat seal measurements shown in Table I were obtained from samplefilm specimens which had been heat sealed together, treated side tountreated side, utilizing a sealing pressure of 5 psi for a duration ordwell time of 2.0 seconds. The values given for the heat seal strengths,expressed in grams per linear inch, represent the force required toseparate the sealed film layers at a rate of about 12 inches per minuteemploying a Suter heat seal tester.

EXAMPLE II A random multipolymer was prepared, following the procedureof Example I, by the polymerization of a 5 mixture of 37.5% by weight ofthe piperylene concentrate; 37.5% by weight of a mixture comprisingdipentene and B-phellandrene present in a weight ratio of about 2:1respectively; and 25.0% by weight of a-methylstyrene. The productmultipolymer resin exhibited Saponification No. 1 (maximum) 20 Viscosity(in toluene 70%) l to 0 Color (50% Toluol Solution) Gardner 5 7Decomposition Temperature 170C.

The resinous multipolymer, when heated under nitrogen at a rate of 10C., per minute, had an initial decomposition temperature of' 170 C.; a2.0% weight loss at 200 C.; a 13.0% weight loss at 300 C.; and a 77.0%weight loss at 400 C.

The resinous multipolymer was blended with polypropylene and fabricatedinto film samples following the procedure outlined in Example I.

In the following Table 11, various physical properties of themultipolymer-containing, biaxially oriented films produced are given andcompared to biaxially oriented polypropylene film devoid of themultipolymer as well as to biaxially oriented film containing theB-pinene prior art additive.

TABLE II Additive None Example 11 Multipolymer B- Pinene Additive by wt:0 10 20 30 30 Haze 2.0 1.3 1.0 0.8 0.8 Gloss 86 90 92 90 92 Modulus MD(MPSI) 488 482 464 453 352 TD 430 436 596 580 535 Elongation MD 8O 95 TD60 65 25 55 Ultimate MD (MPSl) 20.1 23.3 20.4 18.3 15.0 TD 23.6 23.619.4 24.2 22.0 50 Yield MD (MPSI) 8.06 8.3 8.9 8.2

TD 8.53 .10.0 10.4 10.3 Heat Seal Strength (gr/inch) Seal Bar Temp "F 5psi 200 0 1O 3O 45 20 2 sec. 210 0 45 40 25 55 220 O 75 65 i 40 230 O 95180 65 45 240 0 210 50 250 O 95 190 125 40 260 0 45 125 75 60 270 O 240145 80 280 5 65 265 210 60 290 20 55 235 195 EXAMPLE III The piperyleneconcentrate and tertiary butylstyrene were blended to provide a mixturehaving a 4:1 molar ratio of pentadiene 1,3: tertiary butylstyrene,respectively. This mixture was aluminum chloride polymer- 7 ized by theprocedure as set forth in Example I to yield an interpolymer resinhaving the following physical properties:

. 8 I EXAMPLE VI A mixture comprising pentadiene 1,3, isoprene andcyclopentadiene in a molar ratio of about 8 1 1, respectively, wasaluminum chloride polymerized as de- 93.5 gg g' g g gg g scribed inExample I to provide a multipolymer resm of Gardner Color 4 thefollowing properties:

(50% in toluene) Viscosity L (70% in toluene) o a S ifi G i 8:499it'llzeltmg Z01Bnt"() C.) 100 C. 1 d N Wi's mg an a 0 me o J GardnerColor 8 (50% in toluene) EXAMPLE Iv Viscosity G H (70% in toluene) Thepiperylene concentratewas blended with tertiary Specific Gravity 09462butylstyrene to provide a mixture having a 1.79 1 molar ratio ofpentadiene 1 3: tertiary butylstyrene, respectively. This mixture wasaluminum chloride poly- EXAMPLE VII g i g i w a li f res n A mixturecomprising (a) pentad1ene 1,3, isoprene avmg t e O Owmg p yslca proper 1and cyclopentadiene in a molar ratio of about 8 1 1 Melting Point (C.)100.5 respectively, was mixed with (b) beta-pinene in a A l 4 weightratio of about 5 7 1 respectively. This admixf,f f g ture was aluminumchloride polymerized as per Exam- Viscosity k ple 1 to provide a resinof the following properties: (70% in toluene) Specific Gravity 0.9319Iodine N J Melting Point (C.)

' (Ring and Ball) EXAMPLE V Gardner Color 6 (50% in toluene) Theplperylene concentrate and tertiary butylstyrene Z y T U (70 0 intoluene) were blended to yield a mixture having a 2.57 1 molar specificGravity 0.9322 ratio of pentad1ene 1,3: tertiary butylstyrene, respec-3O tively. This mixture was aluminum chloride polymerized as outlined inExample I to yield a copolymer resin having the following Physicalproperties: The multipolymer resins produced 1n accordance wlth Examples111, IV, V, VI and VII were blended with i fig g ggg g 103Cpolypropylene and fabricated into film samples follow- G F Color 4 ingthe procedure outlined in Example I v5 0% n toluene) In the followingTable III, various physical properties 'g$ Q R of the multipolymercontaining films are given and Specific Gravity 0.9524 when compared tothe biaxially oriented polypropylene 9' 9a 81 film devoid of themultipolymer resins.

TABLE III Additive Example 111 Multipolymer Example IV MultipolymerProperty COF F/F .45 .44 .39 .45 .45 .44 .43 .50 F/SS .20 .21 28 .24 .25.20 .27 .25 Haze .9 .8 .8 .8 1.0 .7 .8 .8 Gloss 90.4 90.0 89.1 92.3 91.491.3 91.2 93.5 Ball Burst 72F 14.0 10.9 9.8 7.5 15.0 12.3 10.1 7.6(kg-cm/mil) 0F 9.1 8.8 8.8 6.8 11.1 10.4 7.3 6.1 Tensile Ult. MD 20,30019,700 15,300 13,100 18,900 17,900 15,300 13,700 (psi) TD 23,000 21.90020.600 16,100 23,500 22,200 20,600 17,100 Modulus MD 364 473 455 450 426422 506 422 (kpsi) TD 415 429 506 452 463 411 455 433 Elongation MD 9185 88 95 95 88 68 TD 73 72 77 81 77 73 Handle MD 17.7 20.1 14.8 15.314.3 15.9 15.9 18.0 (1 mil equivalent) TD 19.1 15.4 14.3 17.6 15.6 13.017.5 25.5 Blocking (gm/in) 0.9 3.0 14.7 28.0 0.6 1.5 8.1 10.5 Heat SealsLP (gm/in) 260F 0 10 20 23 0 0 25 0 2 see. V4 psi 280F 5 8 13 23 3 3 2318 300F 20 20 20 23 15 23 23 10 Sentinel (gm/in) 260F 0 18 30 25 0 25 101 1 15 see, 20 psi 280F 3 8 20 25 0 18 33 18 300F 14 18 13 30 9 10 20()0 TABLE 111 Continued Additive Example 111 Multipolymer Example lVMultipolymer Additive Example V Multipolymer Example Vl Multipolymer 10%20% 30% 40% 10% 20% 30% 40% Property COF F/F .42 .36 .44 .51 .44 .45 .40.43 F/SS .20 .21 .10 .23 .21 .18 .21 .24 Haze 1.2 .8 1.0 1.2 1.1 .8 .7.8 Gloss(%) 91.6 90.5 91.4 92.7 83.5 86.9 89.7 91.0 Ball Burst 72F 15.112.0 9.4 7.1 7.5 8.4 7.3 5.9 (kg-cm/mil) OF 12.3 8.3 7.9 5.2 5.5 5.4 6.25.5 Tensile Ult. MD 20,600 20,100 15,900 14,700 11,000 12,000 13,90013,200 (psi) TD 21,500 21,700 18,900 19,600 11,300 11,900 16,300 19,400Modulus MD 447 522 491 449 354 404 422 424 (kpsi) TD 413 454 509 492 325360 451 428 Elongation MD 91 82 67 88 103 85 98 115 TD 75 88 78 85 12788 87 85 Handle MD 11.0 14.3 16.9 19.5 14.7 13.6 14.7 17.1 (1 milequivalent) TD 11.3 18.4 18.2 19.9 13.8 17.8 18.0 19.1 Blocking (gm/in)0.8 2.0 5.0 22.3 1.5 3.2 6.7 13.9 Heat Seals LP (gm/in) 260F 0 8 30 3 1828 2 sec., A psi 280F 5 13 23 13 5 28 38 300F 13 5 25 35 35 43 90 13Sentinel (gm/in) 260F 0 20 5 5 30 30 1% sec., 20 psi 280F 0 13 50 15 188 23 53 300F 10 18 13 5 38 13 33 30 Additive Example V11 Multipolymer10% 40% Property COF F/F .40 .47 .46 .45 F/SS .21 .16 26 .24 Haze .4 .71.0 1.0 Gloss(%) 89.8 92.0 91.0 86.5 BallBurst 7 2L 11.8 13.1 9.6 6.9 V(kg-cm/mil) 0F 10.0 10.2 8.5 6.4 Tensile Ult. MD 20,100 19,100 17,30013,600 (psi) TD 21,600 22,200 20,900 18,400 Modulus MD 488 493 474 453(kpsi) TD 360 506 497 492 Elongation MD 89 62 100 93 TD 85 87 88 95Handle MD 14.7 19.3 16.9 18.6 (1 mil equivalent) TD 14.1 20.6 19.0 18.1Blocking (gm/in) 0.6 2.4 6.0 16.3 Heal Seals LP (gm/in) 260F 0 8 45 20 2sec., V4 psi 280F 5 20 23 18 300F 18 33 43 35 Sentinel (gm/in) 260F 0 1020 13 1% sec., 20 psi 280F 0 20 30 40 300F 13 18 18 30 As seen frompreceding Table 111, polypropylene films containing the additivemultipolymer resins of Examples 3,4,5,6 and 7 exhibited considerablyincreased heat seal strength and a significantly broadened heat sealtemperature range in comparison to the polypropylene film sample devoidof the multipolymer resins. Additionally, the additive containing filmsexhibited increased tensile modulus.

Although the present invention has been described with preferredembodiments, it is to be understood that modifications and variationsmay be resorted to, without departing from the spirit and scope of thisinvention, as those skilled in the art will readily understand.

What is claimed is:

1. A resinous blend composition-comprising a blend of an essentiallyisotactic, crystalline polypropylene containing, a minor amount,sufficient to improve the heat scalability of film prepared therefrom,of from about 5% to about 40% by weight of a normally solid, resinous,random multipolymer of a mixture comprising pentadiene 1,3 and at leastone other compound containing ethylenic unsaturation copolymerizabletherewith.

2. A resinous blend composition in accordance with claim 1 wherein saidmultipolymer comprises pentadiene l-3 copolymerized with a memberselected from the group consisting of cyclopentadiene, isoprene, 2-methylbutene-Z, tertiary butylstyrene, B-pinene, dipentene,B-phellandrene, a-methylstyrene, and mixtures thereof.

3. A resinous blend composition in accordance with claim 1 wherein saidmultipolymer comprises pentadiene 1,3 copolymerized with tertiarybutylstyrene'.

4. A resinous blend composition in accordance with claim 1 wherein saidmultipolymer comprises pentadiene 1,3 copolymerized withcyclopentadiene, isoprene and 2-methylbutene-2.

5. A resinous blend composition in accordance with claim 1 wherein saidmultipolymer comprises pentadiene copolymerized with B-pinene.

6. A resinous blend composition in accordance with claim 1 wherein saidmultipolymer comprises pentadiene 1-3 copolymerized with dipentene,B-phellandrene and a-methylstyrene.

7. A resinous blend, as defined in claim 1, wherein the multipolymer hasa melting point of about 70 to about 125 C.

8. An oriented essentially isotactic crystalline polypropylene filmcontaining a minor amount by weight, sufficient to improve the heat sealcharacteristics of said film, of from about 5% to about 40% by weight ofa normally solid, resinous, random, multipolymer of a mixture comprisingpentadiene l-3 and at least one other hydrocarbon compound containingethylenic unsaturation copolymerizable therewith.

9. A film in accordance with claim 8 wherein said multipolymer comprisespentadiene 1-3 copolymerized with a member selected from the groupconsisting of cyclopentadiene, isoprene, 2-methylbutene-2, tertiarybutylstyrene, B-pinene, dipentene, B-phellandrene, a-methylstyrene, andmixtures thereof.

10. A film in accordance with claim 8 wherein said multipolymercomprises pentadiene 1,3 copolymerized with tertiary butylstyrene.

11. A film in accordance with claim 8 wherein said multipolymercomprises pentadiene l-3 copolymerized with cyclopentadiene, isopreneand 2-methylbutene-2.

12. A film in accordance with claim 8 wherein said multipolymercomprises pentadiene copolymerized with B-pinene.

13. A film as defined in claim 8 wherein the multipolymer has a meltingpoint of from about to about C.

14. A film in accordance with claim 8 wherein said multipolymercomprises pentadiene 1-3 copolymerized with dipentene, B-phellandreneand a-methylstyrene.

15. An oriented, crystalline, polypropylene film, as defined in claim 8,containing about 5% to about 40% by weight of a normally solid,resinous, random, multipolymer of a mixture comprising from about 15% toabout 30% by weight of pentadiene l-3,- from about 20% to about 40% byweight of a-methylstyrene, from about 5% to about 30% by weight ofdipentene, and from about 2% to about 15% by weight of Bphellandrene.

16. An oriented, crystalline, polypropylene film as defined in claim 15wherein said multipolymer has a melting point of from about 70 to about125C.

1. A RESINOUS BLEND COMPOSITION COMPRISING A BLEND OF AN ESSENTIALLYISOTACTIC, CRYSTALLINE POLYPROPYLENE CONTAINING, A MINOR AMOUNT,SUFFICIENT TO IMPROVE THE LEAST SEALABILITY OF FILM PREPARED THEREFROM,OF FROM ABOUT 5% TO ABOUT 40% BY WEIGHT OF A NORMALLY SOLID, RESINOUS,RANDOM MULTIPOLYMER OF A MIXTURE COMPRISING PENTADINE 1,3 AND AT LEASTONE OTHER COMPOUND CONTAINING ETHYLENIC UNSATURATION COPOLYMERIZABLETHEREWITH.
 2. A resinous blend composition in accordance with claim 1wherein said multipolymer comprises pentadiene 1-3 copolymerized with amember selected from the group consisting of cyclopentadiene, isoprene,2-methylbutene-2, tertiary butylstyrene, Beta -pinene, dipentene, Beta-phellandrene, Alpha -methylstyrene, and mixtures thereof.
 3. A resinousblend composition in accordance with claim 1 wherein said multipolymercomprises pentadiene 1,3 copolymerized with tertiary butylstyrene.
 4. Aresinous blend composition in accordance with claim 1 wherein saidmultipolymer comprises pentadiene 1,3 copolymerized withcyclopentadiene, isoprene and 2-methylbutene-2.
 5. A resinous blendcomposition in accordance with claim 1 wherein said multipolymercomprises pentadiene copolymerized with Beta -pinene.
 6. A resinousblend composition in accordance with claim 1 wherein said multipolymercomprises pentadiene 1-3 copolymerized with dipentene, Beta-phellandrene and Alpha -methylstyrene.
 7. A resinous blend, as definedin claim 1, wherein the multipolymer has a melting point of about 70* toabout 125* C.
 8. An oriented essentially isotactic crystallinepolypropylene film containing a minor amount by weight, sufficient toimprove the heat seal characteristics of said film, of from about 5% toabout 40% by weight of a normally solid, resinous, random, multipolymerof a mixture comprising pentadiene 1-3 and at least one otherhydrocarbon compound containing ethylenic unsaturation copolymerizabletherewith.
 9. A film in accordance with claim 8 wherein saidmultipolymer comprises pentadiene 1-3 copolymerized with a memberselected from the group consisting of cyclopentadiene, isoprene,2-methylbutene-2, tertiary butylstyrene, Beta -pinene, dipentene, Beta-phellandrene, Alpha -methylstyrene, and mixtures thereof.
 10. A film inaccordance with claim 8 wherein said multipolymer comprises pentadiene1,3 copolymerized with tertiary butylstyrene.
 11. A film in accordancewith claim 8 wherein said multipolymer comprises pentadiene 1-3copolymerized with cyclopentadiene, isoprene and 2-methylbutene-2.
 12. Afilm in accordance with claim 8 wherein said multipolymer comprisespentadiene copolymerized with Beta -pinene.
 13. A film as defined inclaim 8 wherein the multipolymer has a melting point of from about 70*to about 125* C.
 14. A film in accordance with claim 8 wherein saidmultipolymer comprises pentadiene 1-3 copolymerized with dipentene, Beta-phellandrene and Alpha -methylstyrene.
 15. An oriented, crystalline,polypropylene film, as defiNed in claim 8, containing about 5% to about40% by weight of a normally solid, resinous, random, multipolymer of amixture comprising from about 15% to about 30% by weight of pentadiene1-3, from about 20% to about 40% by weight of Alpha -methylstyrene, fromabout 5% to about 30% by weight of dipentene, and from about 2% to about15% by weight of Beta phellandrene.
 16. An oriented, crystalline,polypropylene film as defined in claim 15 wherein said multipolymer hasa melting point of from about 70* to about 125*C.